A normal person, while sleeping, generally turns or moves frequently. This mobility restores blood circulation to the compressed areas of the subcutaneous tissues. When a patient is partially or permanently immobilized, the blood supply in the area under pressure is restricted or blocked. If the blood supply is not restored it will be predisposed to induce local injury, which might lead to decubitus or pressure ulcers (bedsores). Pressure sores occur most commonly in the buttocks, sacrum, hips and heels. When infected, these sores can become life threatening. Besides pressure ulcers, immobility can cause other pathologies including pneumonia, atelectasis, thrombosis, urinary tract infections, muscle wasting, bone demineralization and other undesired events.
To prevent such complications, many medical care facilities buy or rent extraordinarily expensive beds and therapeutic support surfaces, costing upwards of seventy-five thousand dollars each or more than $100/day in rent. Other medical and nursing care facilities rely on nurses and aides to turn bedridden patients manually, preferably at least every 2 hours—day and night—to relieve tissue compression and reestablish blood flow. Both alternatives put a significant strain on limited medical care resources.
The manual procedure, in particular, has many drawbacks. The need to frequently turn and move patients is costly, and requires an increased ratio of personnel to patient. The immobilized patient is also awakened every time he is mobilized. If family members are the caregivers, they need to be in attendance 24 hours a day, which might lead to fatigue and distress.
Many attempts have been made to solve the above-mentioned problems utilizing mattresses filled with air, water or gel. These solutions generally fall into one or both of two categories—very expensive solutions, and inadequate or unreliable solutions. Today, the medical bed industry has largely abandoned strictly or predominantly mechanical approaches in favor of costly therapeutic support surfaces that use managed multi-compartment air mattresses to distribute pressure and laterally rotate the patient. These approaches, moreover, have drawbacks in that patients typically float unsecured on the patient support surface. Thus, there is still a very great need for fresh, less costly solutions to problems of patient immobility.